Enhanced multiplexing for single rlc entity

ABSTRACT

A method and apparatus for interrupting the lower priority packet transmission/reception for higher priority packet transmission/reception within the context of a common RLC entity is provided herein. The transmission/reception of lower priority data blocks containing data segments of a first higher layer packet is interrupted to transmit/receive higher priority data blocks containing data segments of a second higher layer packet. After the transmission/reception of a final segment of the second higher layer packet, the transmission/reception of the first higher layer packet is resumed. In some embodiments, a final segment of the second higher layer packet is encapsulated in a final higher priority data block with a remaining data segment of the first higher layer packet. The final higher priority data block further includes a transition indicator to indicate a transition from the second higher layer packet back to the first higher layer packet.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/143,313, filed on 2 Aug. 2011, which was the National Stage ofInternational Application No. PCT/IB10/53826, filed 25 Aug. 2010, whichclaimed the benefit of U.S. Provisional Application Ser. No. 61/237,744,filed 28 Aug. 2009, and U.S. Provisional Application Ser. No.61/261,118, filed 13 Nov. 2009. The entire contents of U.S. patentapplication Ser. No. 13/143,313, U.S. Provisional Application Ser. No.61/237,744, and U.S. Provisional Application Ser. No. 61/261,118 areincorporated by reference herein for all purposes.

TECHNICAL FIELD

The present invention relates generally to radio link control (RLC)protocols for wireless communication networks, and more particularly tomethods and apparatuses for interrupting and resuming transmissions onan RLC data block basis for different priority packet flows within asingle RLC entity.

BACKGROUND

RLC is a protocol used in wireless communication networks to convey userplane or control plane information between a mobile station and a radioaccess network. When conveying user plane information, the RLC protocolreceives a protocol data unit (PDU) from a higher layer known as thelogical link control (LLC) layer, where each LLC PDU is associated witha packet flow context (PFC) and is divided into smaller data packets,referred to herein as RLC data blocks for transmission over the wirelesscommunication channel to a receiver. The receiver reassembles the LLCPDU from the received RLC data blocks.

In some scenarios, the RLC protocol entity operating at a transceiverand a receiver may support the transmission and reception of multiplepacket data sessions in parallel, whereby multiple PFCs share a commonRLC entity. Each PFC has its own packet data protocol (PDP) context, andtherefore has its own quality of service (QoS) attributes from which atransmission priority may be derived. When a common RLC entity supportsmultiple PFCs, the transmitting RLC entity may receive LLC PDUscorresponding to these PFCs asynchronously and generally decides whichPFC to service on a per LLC PDU basis, which requires the RLC entity tocomplete a transmission of an LLC PDU in progress before beginning thetransmission of the next LLC PDU. A higher priority LLC PDU maytherefore incur undesirable transmission delays while the common RLCentity completes the transmission of a lower priority LLC PDU. Suchdelays may cause perceivable degradation of the service supported by thehigher priority LLC PDU, especially when the lower priority LLC PDU hasa significant length.

SUMMARY

The present invention overcomes the priority-based problems associatedwith the use of a common RLC entity by providing a method and apparatusfor interrupting the transmission/reception of lower priority higherlayer packets to transmit/receive higher priority higher layer packetswithin the context of a common RLC entity. An RLC entity views LLC PDUsas higher layer packets. It will be appreciated that the presentinvention applies to both the uplink and downlink of a wirelesscommunication network.

According to one exemplary embodiment, lower priority data blocks (alsoreferred to herein as RLC data blocks) containing data segments of afirst higher layer packet associated with a lower priority first PFCexperience ongoing transmission to a receiver. The transmission of thefirst higher layer packet is interrupted to transmit higher prioritydata blocks containing data segments of a second higher layer packetassociated with a higher priority second PFC. After the transmission ofa final data segment of the second higher layer packet, the transmissionof the first higher layer packet is resumed. In one exemplaryembodiment, the lower priority data blocks are sequentially numberedbefore the interruption, and the sequential numbering continues withoutsequence number restart for the interrupting higher priority data blocksand the resuming lower priority data blocks.

The receiver receives the lower priority data blocks. Upon receipt ofthe first higher priority data block, the receiver detects aninterruption of the first higher layer packet. The interruption of thefirst higher layer packet continues until a final higher priority datablock containing a final data segment of the second higher layer packetis received, after which the reception of the first higher layer packetresumes.

The present invention also provides a method and apparatus that moreefficiently bundles data segments associated with different higher layerpackets during the transition from the interrupting higher layer packetback to the interrupted higher layer packet. More particularly, a finaldata segment of a first higher layer packet associated with a higherpriority first PFC is encapsulated in a final higher priority data blockalong with a data segment of a second higher layer packet associatedwith a lower priority second PFC to complete a transmission of the firsthigher layer packet and to resume a transmission of the second higherlayer packet. The final higher priority data block further includes atransition indicator to indicate a transition within the final higherpriority data block from the first higher layer packet back to thesecond higher layer packet.

The receiver receives the final higher priority data block comprisingthe final data segment of the first higher layer packet, a remainingdata segment of the second higher layer packet, and the transitionindicator. The receiver separates the remaining data segment for thesecond higher layer packet from the final higher priority data blockbased on the transition indicator to resume a previously interruptedreception of the second higher layer packet.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows one exemplary mobile communication system providing aconnection to an external packet data network.

FIG. 2 shows one exemplary protocol stack for a mobile communicationsystem for transmitting data packets between a mobile terminal and anexternal packet data network.

FIG. 3 shows one exemplary simplified block diagram of the relationshipbetween the common RLC entity and the higher layer packets at thetransmitter and the receiver.

FIG. 4 shows one exemplary transmission method for interrupting andresuming higher layer packet transmissions within the context of acommon RLC entity.

FIG. 5 shows one exemplary reception method for interrupting andresuming higher layer packet receptions within the context of a commonRLC entity.

FIG. 6 shows one exemplary scenario for interrupting and resuming higherlayer packet transmissions using a common RLC entity.

FIG. 7 shows one exemplary method for encapsulating data segments fromdifferent higher layer packets for transmission via a single data blockwithin the context of a common RLC entity.

FIG. 8 shows one exemplary method for separating data segments fromdifferent higher layer packets received in a single data block withinthe context of a common RLC entity.

FIG. 9 shows another exemplary scenario for interrupting and resumingpacket transmission using a common RLC entity.

FIG. 10 shows a block diagram of a transmitter and receiver according toone exemplary embodiment of the present invention.

DETAILED DESCRIPTION

The present invention provides a method and apparatus for interruptingthe transmission/reception of a lower priority LLC PDU on a per RLC datablock basis to transmit a higher priority LLC PDU within the context ofa common RLC entity. The transmission/reception of RLC data blockscontaining data segments of a lower priority LLC PDU associated with alower priority PFC is interrupted to transmit RLC data blocks containingdata segments of a higher priority LLC PDU associated with a higherpriority PFC. After the transmission/reception of a final data segmentof the higher priority LLC PDU within an RLC data block, thetransmission/reception of the lower priority LLC PDU resumes, eitherwithin the same RLC data block or within a subsequent RLC data block.The interrupting and resuming transitions described herein reducesundesirable transmission delays by using an RLC data block-basedtransmission granularity to ensure that the relative priorities of thePFCs are honored to the greatest extent possible when multiple PFCsshare a common RLC entity. It will be appreciated that the RLC processesdescribed herein may be used by a mobile station on the uplink and/or bya base station on the downlink.

To facilitate the description of the present invention, the followingfirst describes an exemplary mobile communication system based on theEnhanced General Packet Radio Service (EGPRS) standard by the ThirdGeneration Partnership Project (3GPP), and subsequently describes thepresent invention in the context of an EGPRS mobile communicationsystem. It will be appreciated, however, that the present inventionapplies to other communication protocols that use a common RLC entity totransmit multiple distinct packet data sessions in parallel. Further, itwill be appreciated the present invention applies to both downlink anduplink communications.

FIG. 1 shows an exemplary EGPRS network 10 comprising a GSM/EGPRS radioaccess network (GERAN) 12 and a core network 16. GERAN 12 typicallycomprises one or more base station subsystems (BSSs) 14. While notexplicitly shown, each BSS 14 comprises a base station controller (BSC)and one or more base transceiver stations (BTSs), which may beco-located or in separate locations. The BTSs comprise the antennas, RFequipment, and baseband processing circuits needed to communicate withmobile terminals 100. The BSC manages the radio resources used forcommunication with the mobile terminal 100 and provides a connection tothe core network 16.

Core network 16 includes one or more serving GPRS support nodes (SGSNs)18 and one or more gateway GPRS support node (GGSN) 20. The SGSN 18provides support for packet switched communications, handles sessionmanagement and mobility management functions for the packet switchedservices, and provides a connection to a GGSN 20. The GGSN 20 serves asa gateway between the core network 16 network and external packet datanetworks 30, e.g., the Internet. For packet data communication, themobile terminal 100 establishes a communication session with an SGSN 18,and the GGSN 20 connects the SGSN 18 with the external packet datanetworks 30. A more detailed description of the core network 16 isreadily available in the relevant EGPRS standards.

FIG. 2 provides a simplified illustration of an EGPRS protocol stack 50used for transmission of packet data between the mobile terminal 100 andSGSN 18. Protocol stack 50 includes a plurality of protocol layers. Thevarious layers of the protocol stack 50 represent a set of programs andprotocols that may be implemented by software running on a hostcomputing device including a processor and memory. Each layerencapsulates data received from a higher layer protocol to generateprotocol data units (PDUs) that are passed down to the next lower layer.The term PDU as used herein is synonymous with the term packet.

The SGSN 18 receives IP packets from the GGSN 20. IP packets or otherdata packets may, for example, be transmitted to the SGSN 18 using theGPRS tunneling protocol (GTP). The protocol stack 50 implemented by theSGSN 18 and mobile terminal 100 includes a Sub Network DependentConvergence Protocol (SNDCP) layer, Logical Link Control (LLC) layer,Radio Link Control (RLC) layer, Medium Access Control (MAC) layer, and aPhysical layer (PL). The SNDCP layer converts the IP packets into aformat compatible with the underlying GPRS network architecture. SNDCPPDUs are passed to the LLC layer, which provides a logical connectionbetween the SGSN 18 and mobile terminals 100. The LLC layer encapsulatesthe SNDCP PDUs with an LLC header to generate LLC PDUs. The Base StationSystem GPRS Protocol (BSSGP) layer (not shown) routes the LLC PDU to theserving BSS 14 (e.g., over a frame relay PL). The BSSGP operates betweenthe SGSN 18 and the BSS 14, e.g., the BSSGP does not extend over the airinterface.

At the BSS 14, an LLC relay provides the LLC PDU to the RLC layer. AnRLC entity establishes a reliable link (e.g., if required by the QoS ofthe corresponding packet switched service) between the BSS 14 and mobileterminal 100. The RLC entity also performs segmentation and reassemblyof upper-layer PDUs (LLC PDUs in this example) into RLC packets, whichare referred to herein as RLC data blocks. Each RLC data block includesa header and a data field. The header includes a temporary flow identity(TFI) that uniquely maps to a PFC, and the data field includes datasegments from the LLC PDU associated with the PFC uniquely identified bythe TFI in the corresponding header. The RLC data blocks are passed tothe MAC layer which encapsulates the RLC data blocks with MAC headers.The MAC layer controls access signaling across the air interface,including the assignment of uplink and downlink radio blocks which areused to carry the RLC data blocks. The data is then transmitted to amobile terminal 100 over the air interface via the PL. The PL isresponsible for converting data received from the MAC layer into a bitstream suitable for transmission to the mobile terminal 100 over theradio interface.

The RLC layer of the BSS 14 and/or mobile terminal 100 may support thetransmission and reception of multiple packet data sessions in parallel,whereby each packet session has a corresponding PFC and multiple PFCsshare a common RLC entity. Each LLC PDU is uniquely associated with adistinct PFC, where each PFC has a particular transmission priority andQoS. For example, an LLC PDU associated with a lower priority PFC, e.g.,LLC PDU_(L), may share a common RLC entity with an LLC PDU associatedwith a higher priority PFC, e.g., LLC PDU_(H), as shown in FIG. 3.Conventional systems operate using an LLC PDU-based transmissiongranularity, and therefore require the RLC entity to complete thetransmission/reception of the RLC data blocks associated with a specificLLC PDU before beginning the transmission/reception of the RLC datablocks associated with a different LLC PDU. As a result, thetransmission and reception of data for a higher priority LLC PDU may beundesirably delayed while the RLC entity completes thetransmission/reception of data blocks for a lower priority LLC PDU.

The present invention addresses this problem by providing a method andapparatus for interrupting RLC data block transmissions for a lowerpriority PFC in favor of RLC data block transmission for a higherpriority PFC within the context of a single RLC entity. FIG. 4 shows oneexemplary method 200 for interrupting and resuming lower prioritytransmissions. In general, the RLC entity transmits RLC data blockscontaining data segments of an LLC PDU associated with the lowerpriority PFC (LLC PDU_(L)) (block 210), where the lower priority RLCdata blocks are sequentially numbered. The RLC entity interrupts thetransmission of LLC PDU_(L) by transmitting one or more RLC data blockscontaining data segments of an LLC PDU associated with the higherpriority PFC (LLC PDU_(H)) (block 220). The higher priority RLC datablocks are also sequentially numbered, where the sequential numbering iscontinued from the lower priority RLC data blocks without a sequencenumber restart. After transmitting a final data segment of LLC PDU_(H)within an RLC data block, the RLC entity resumes the transmission ofdata segments associated with LLC PDU_(L), either within the same RLCdata block or within a subsequent RLC data block (block 230). Theresuming lower priority RLC data blocks are also sequentially numbered,where the sequential numbering is continued from the higher priority RLCdata blocks without a sequence number restart.

FIG. 5 shows one exemplary interrupting and resuming method 250 from theperspective of the receiver. In general, the RLC entity receives RLCdata blocks containing data segments for the LLC PDU_(L) (block 260),where the lower priority RLC data blocks are sequentially numbered. TheRLC entity detects an interruption of the LLC PDU_(L) upon receiving anRLC data block containing a data segment for the LLC PDU_(H) (block270). The higher priority RLC data blocks are also sequentiallynumbered, where the sequential numbering is continued from the lowerpriority RLC data blocks without a sequence number restart. Afterreceiving a final data segment of the LLC PDU_(H) within an RLC datablock (block 280), the RLC entity resumes the reception of the datasegments of the LLC PDU_(L) (block 290), which may be contained withinthe same RLC data block or within a subsequent RLC data block. Theresuming lower priority RLC data blocks are also sequentially numbered,where the sequential numbering is continued from the higher priority RLCdata blocks without a sequence number restart.

To successfully implement the interrupting and resuming transitions ofthe present invention, the RLC entity signals the interrupting and/orresuming transitions. The RLC entity may signal the interruptingtransition by changing the temporary flow identity (TFI) of theinterrupting RLC data block. For example, the RLC entity may change theTFI in the header of the interrupting RLC data blocks from TFI_(L),which is uniquely associated with the lower priority PFC, to TFI_(H),which is uniquely associated with the higher priority PFC. Similarly,the RLC entity may signal the resuming transition by including TFI_(L)in the header of the resuming RLC data blocks. For example, the headerof the of the initial and resuming lower priority RLC data blocks mayeach include TFI_(L), while the header of the interrupting higherpriority RLC data blocks may each include TFI_(H). It will beappreciated that the data fields of the RLC data blocks contain datasegments associated with the PFC identified by the header TFI.

In another embodiment, the RLC entity signals the interruptingtransition by including TFI_(H) in the header of the higher priority RLCdata blocks, and includes TFI_(H) along with a transition indicator inthe data field of the first interrupting higher priority RLC data block.By including the transition indicator and TFI_(H) in the data field ofthe first interrupting higher priority RLC data block, the receiving RLCentity is able to detect the precise point of interruption within thesequence of received RLC data blocks, even if the receiver did notsuccessfully receive the RLC data block immediately previous to thefirst interrupting higher priority RLC data block. The RLC entitysignals the resuming transition by including TFI_(L) and a transitionindicator in the data field of the first resuming RLC data block, andincluding TFI_(L) in the header of all resuming lower priority RLC datablocks. By including the transition indicator and TFI in the data fieldof the first resuming RLC data block, the RLC entity enables thereceiver to detect the transition, even if the receiver did notsuccessfully receive the RLC data block immediately previous to thefirst resuming higher priority RLC data block. The interruptingtransition indicator may be the same as or different from the resumingtransition indicator. For example, a length indicator (LI) set to 124 or125 may be used to indicate an interrupting and/or resuming transitions.

FIG. 6 shows one example of multiplexed RLC data blocks 60 associatedwith different priority PFCs 70, 80 within the context of a single RLCentity. The RLC data blocks 60 of FIG. 6 may represent transmission orreception data blocks. While FIG. 6 illustrates the RLC data blocks 60for the embodiment that includes a transition indicator in the datafield, it will be appreciated that the present invention is not limitedto this embodiment.

Each RLC data block 60 includes a header and a data field, where eachdata field may carry up to X octets of data, and where a data segmentfrom an LLC PDU uses one or more consecutive data field octets. In thisexample, the LLC PDU associated with the lower priority PFC 70 (LLCPDU_(L)) requires 3.5 RLC data blocks 60, while the LLC PDU associatedwith the higher priority PFC 80 (LLC PDU_(H)) requires 2.25 RLC datablocks 60, resulting in the RLC entity using seven RLC data blocks 60sequentially numbered with block sequence numbers (BSNs) 1 to 7 for LLCPDU_(L) and LLC PDU_(H). The transitions from the lower priority PFC 70to the higher priority PFC 80 and back to the lower priority PFC 70 donot initiate a BSN sequence number restart. In other words, a singlecontiguous sequence of BSN values is present in the RLC data blocks 60,even when successive RLC data blocks 60 contain data segments fromdifferent PFCs.

The header of each RLC data block 60 includes a TFI that uniquelyassociates the data segments in the corresponding data field with aspecific PFC. For example, TFI_(L) in the header of BSN 1, BSN 2, BSN 6,and BSN 7 associates the data segments in the corresponding data fieldswith the lower priority PFC 70. To signal the interrupting transition ofthe lower priority PFC 70 by the higher priority PFC 80, the RLC entitychanges the TFI in the header of the interrupting RLC data blocks 60 toTFI_(H), and puts data segments for LLC PDU_(H) in the correspondingdata fields. The data field of the first interrupting RLC data block 60,e.g., BSN 3, may also signal the interrupting transition by optionallyincluding TFI_(H) and a transition length indicator (LI) set to apredetermined transition value, e.g., 124 in the first two octets of thedata field. As shown in FIG. 6, when the data field includes atransition indicator, the data field has fewer octets available forpayload data segments, e.g., two fewer octets in BSN 3 and three feweroctets in BSN 5.

To signal the resuming transition of the lower priority PFC 70, the RLCentity changes the TFI in the header of the resuming RLC data blocks 60back to TFI_(L), and puts the remaining data segments of the lowerpriority LLC PDU in the corresponding data fields. The data field of thefirst resuming RLC data block 60, e.g., BSN 6, may further signal theresuming transition by including TFI_(L) and a transition LI set to apredetermined transition value, e.g., 124, in the first two octets ofthe data field.

As shown in FIG. 6, the data fields of some RLC data blocks 60, e.g.,BSN 5 and BSN 7, may not be completely full with data. For example, thehigher priority LLC PDU does not need all of the octets available in BSN5 to complete the higher priority transmission/reception. In this case,an octet of the data field may identify the number of octets containingdata for the last data segment of the higher priority LLC PDU byincluding an LI set to a value equal to the number of octets needed tocomplete the transmission/reception of LLC PDU_(H), e.g., LI=0.25X+2. Anoctet of the data field may also optionally be used to include an LI setto a filler value, e.g., 127, to signal that the portion of the datafield not filled with octets corresponding to the last data segment ofthe higher priority LLC PDU contains filler octets (e.g., dummy data).

The above discloses how the RLC entity may interrupt the lower priorityPFCs in favor of higher priority PFCs, and therefore, to prevent anyundesirable transmission/reception delays. When transitioning from thelower priority PFC to the higher priority PFC, the last RLC data blocksent for the lower priority LLC PDU before the interruption willtypically not contain the final data segment of the lower priority LLCPDU, and therefore the data field will be full. Thus, there is typicallyno inefficiency experienced during the transition from the lowerpriority PFC to the higher priority PFC. However, when transitioningfrom the higher priority PFC back to the lower priority PFC, the finalhigher priority RLC data block may not need all of the available payloadspace within the data field to complete the transmission/reception ofthe higher priority LLC PDU, as shown in FIG. 6, which leads toinefficiencies at the RLC layer due to the unused payload space. Thefollowing describes how to improve RLC data block packing efficiency forboth the uplink and downlink during transitions from higher priorityPFCs back to lower priority PFCs within the context of a single RLCentity. More particularly, the following describes how data segmentsfrom LLC PDUs corresponding to different PFCs may be encapsulated into asingle RLC data block during the transition from the higher priority PFCback to the lower priority PFC to avoid wasting available payload space.

FIGS. 7 and 8 show an encapsulation method 300, 350 for the transmitterand receiver, respectively. At the transmitter, one or more datasegments, including the final data segment of a higher priority LLC PDU,is encapsulated along with one or more remaining data segments of thelower priority LLC PDU associated with a previously interrupted lowerpriority PFC in the data field of a final higher priority RLC data block(block 310). The final higher priority RLC data block further includes atransition indicator to indicate the transition within the final higherpriority RLC data block from the higher priority PFC back to the lowerpriority PFC (block 320). Upon receipt of the RLC data block containingdata segments for both a higher priority PFC and a lower priority PFC(block 360), the RLC entity in the receiver separates the lower prioritydata segments from the data block based on the number of octets used forthe last data segments of the higher priority PFC and a transitionindicator included with the data block (block 370). In both thetransmission and the reception embodiments, the transition indicator maycomprise a transition LI set to a predetermined transition value (e.g.,124 or 125) in the data field of the final higher priority RLC datablock. The transition indicator may further comprise a data field TFIthat differs from the header TFI, where the header TFI signals theassociation of a first set of data segments in the data field to thehigher priority PFC, and the data field TFI signals the association of asecond set of data segments in the data field to the different lowerpriority PFC.

FIG. 9 shows one example of multiplexed transmission or reception RLCdata blocks associated with different priority PFCs within the contextof a single RLC entity, where at least one of the RLC data blocks usesthe encapsulation method described above to more efficiently transmitand receive data segments associated with different PFCs during thetransition from the higher priority PFC 80 back to the lower priorityPFC 70. As with FIG. 6, the lower priority PFC 70 requires 3.5 RLC datablocks, while the higher priority PFC 80 requires 2.25 RLC data blocks.Because of the disclosed encapsulation method, however, the RLC entityfor this embodiment only uses six RLC data blocks 60 sequentiallynumbered with block sequence numbers (BSNs) 1 to 6 for the same lowerand higher priority LLC PDUs of FIG. 6. In the example of FIG. 9, RLCdata blocks BSN 1 to BSN 4 are identical to that of FIG. 5. Thus, theinterruption details provided above are not repeated here.

To more efficiently make the transition from the higher priority PFCback to the lower priority PFC, the RLC entity generates a final higherpriority RLC data block 60, e.g., BSN 5, that encapsulates both thefinal higher priority data segment and a remaining lower priority datasegment in a single RLC data block 60. The header of BSN 5 includesTFI_(H) to signal that at least a portion of BSN 5 includes payloadcorresponding to the higher priority PFC. The data field of BSN 5includes an LI set to a value equal to the number of octets needed tocomplete the transmission of the final data segment of LLC PDU_(H),e.g., LI=0.25X+2, a transition LI set to a predetermined transitionvalue, e.g., LI=124, and TFI_(L). The remainder of the data fieldincludes the last 0.25X+2 octets of LLC PDU_(H), followed by the next0.75X−5 octets of LLC PDU_(L). BSN 6 completes the transmission of LLCPDU_(L).

As shown in FIG. 9, the data field of some of the RLC data blocks 60,e.g., BSN 6, may not be completely full. For example, the LLC PDU_(L)does not need all of the octets available in BSN 6 to complete the lowerpriority transmission/reception. In this case, the data field of BSN 6may optionally include an additional LI set to a filler value, e.g.,LI=127 to signal that the portion of the data field not filled with datacorresponding to the last data segment of the lower priority LLC PDUcontains filler octets (e.g., dummy data). It will further beappreciated that if BSN 5 includes more octets than needed to completethe transmission of the LLC PDU_(H) and LLC PDU_(L), BSN 5 may alsoinclude additional LI values, e.g., an LI set to a value equal to thenumber of octets needed to complete the transmission of the LLC PDU_(L),and an LI set to a filler value, e.g., LI=127.

FIG. 10 illustrates an exemplary communication terminal 400 forimplementing the interrupting and resuming transitions within thecontext of a single RLC entity as described herein. Communicationterminal 400 may represent a receiver or a transmitter, and may comprisea mobile terminal 100 or base station 14. The communication terminal 400includes a transceiver 402 coupled to an antenna 404 for transmittingand receiving signals. Baseband processor 406 processes signalstransmitted to, and received by, the communication terminal 400.Exemplary processing performed by baseband processor 406 includesmodulation/demodulation, interleaving/de-interleaving, coding/decoding,etc. The baseband processor 406 includes an RLC processor 408 forimplementing RLC protocols as described herein. As described above, RLCprocessor 408 performs the interrupting and resuming transitions of thelower and higher priority data within the context of a single RLCentity. When the RLC entity resumes lower priority transmissions, theRLC processor 408 may be configured to encapsulate the final higherpriority data segment(s) along with one or more remaining lower prioritydata segments in a single RLC data block.

The present invention is described in terms of a single interruption ofa lower priority PFC in favor of a higher priority PFC within thecontext of a common RLC entity. It will be appreciated, however, thatany number of interrupting transitions may occur. For example, thetransmission/reception of a first lower priority PFC may be interruptedmultiple times to enable the transmission/reception of LLC PDUsassociated with multiple higher priority PFCs. Further, the interruptingtransitions may be stacked such that two or more interruptingtransitions occur before the transmission/reception of a lower priorityLLC PDU is resumed. For example, the transmission/reception of a lowerpriority LLC PDU (PDU-A) may be interrupted to transmit/receive a higherpriority LLC PDU (PDU-B). The transmission/reception of PDU-B may inturn be interrupted to transmit/receive an even higher priority LLC PDU(PDU-C). It will also be appreciated that a final higher priority RLCdata block may include data segments from LLC PDUs associated with morethan two PFCs. For example, a final higher priority RLC data block mayinclude the final data segment(s) of PDU-C, the final data segment(s) ofPDU-B, and one or more remaining data segments of PDU-A.

The present invention may, of course, be carried out in other ways thanthose specifically set forth herein without departing from essentialcharacteristics of the invention. The present embodiments are to beconsidered in all respects as illustrative and not restrictive, and allchanges coming within the meaning and equivalency range of the appendedclaims are intended to be embraced therein.

1. A method of transmitting data packets from a transmitter to areceiver within the context of a single radio link control (RLC) entity,the method comprising: transmitting lower priority data blockscontaining data segments of a first higher layer packet associated witha lower priority first packet flow context (PFC); interrupting thetransmission of said first higher layer packet to transmit higherpriority data blocks containing data segments of a second higher layerpacket associated with a higher priority second PFC; and resuming thetransmission of said first higher layer packet after transmission of afinal data segment of said second higher layer packet.